Do investment bankers really keep deal details confidential? How do professional poker players keep their cool? What is it like to toil 1.5 kilometres below the surface of the earth?

The answers may be hum-drum to the people in these professions, but there are plenty of behaviours or conditions people take for granted in their offices that would amaze or baffle outsiders.

Curious? So was BBC Capital. We turned to question-and-answer site Quora.com, for answers from everyday employees, to the question: “what is something that is common knowledge at your workplace, but would be mind-blowing for the rest of us?”

How’s the weather down there?

Deep mines aren’t just dark and extensive. They can develop their own weather system, wrote Mikko Tikkanen, who once worked at one of the biggest mines in Europe, located in Finland.

“In certain conditions, thick mists/clouds can form in certain heights,” wrote Tikkanen. Yet, there are no seasons. “The bedrock itself is actually so warm that the temperatures down there are the same (about +25C) whether it's summer or winter, with -30 C outside.”

In some mines, there’s a quasi-town set up. “Down in 1.5km main level, everything's well lit, the walls are white (think of your basic underground garage), there are offices, repair and part shops, restaurant, sauna and even a cell ‘tower’, so your cell phone works down there. Everything is done with big machines that have soundproof and air conditioned cabins, with MP3 players etc. The machines can also be operated remotely or even operate completely independently, by themselves.”

The reality is far less glamorous, wrote Harry Wong, a former investment banker. “'Investment' banking has little to do with investments,” wrote Wong. “You are really a 'salesman.”

Hours are long and junior investment bankers have a tough life. “If you are a junior investment banker, you spend most of your time putting together PowerPoint presentations/memos,” wrote Wong.

“You really don't want to see how the sausage was made,” Wong added. “Opinions range from educated guesses to made-up-stuff [that] frequently masquerades as facts and well-researched advice. I've seen and performed my fair share of number fudging/massaging to justify a conclusion.”

But maybe more surprising: confidentiality isn’t part of the deal. “Confidential and private information are rarely treated as such. People can't help talking about what they are working on.”

High on poker

Some online poker players like to use marijuana or other drugs while playing, wrote Joshua Goldstein, a former professional poker player. “(They) say it calms their nerves, especially when they are playing a whole host of tables.”

Another surprising norm: even if a player wins a tournament with a big money prize, they usually won’t go home rich.

“Most tournament poker players are ‘backed,’” wrote Goldstein. That means someone likely paid their entry fee or provided the cash needed to play, in return for a share of any winnings. “If you win a tournament for $1M, but your backer has put you in $500,000 of tournaments without a payout, the $500,000 comes out of the winnings (and gets paid back to the backer) before you split the profits... What this means is that most tournament players do not have 100% of themselves in any tournament.”

Working with the criminally insane

A facility for mentally ill criminals does not have the chaos and violence depicted on television dramas, wrote Bianca Diesel, a former nurse on a forensic unit of a state psychiatric hospital.

As a nurse in a facility for mentally ill criminals, Diesel worked with “murderers, rapist, arsonists (and) child molesters”. Mental illness does not discriminate, she wrote. “We had doctors, lawyers, electrical engineers, etc there. No one is safe from mental illness.”

The most addictive drug she has encountered as a nurse? “My patients quit every kind of drug known. The hardest drug for them to quit is nicotine. Smoking.”

Behind the camera

During the filming of a big-screen movie, does anyone actually say, “Lights, Camera, Action”? Not any more according to film production student Aladdin Steiman-Cameron.

“This is a hold-over from when film was much less sensitive, and it was costly/dangerous to leave studio lights on for long periods of time,” Steiman-Cameron wrote. “Also notice that there's nothing in there about sound. What they actually say is more like this: "Quiet please! Ready? Roll sound..."

How do you like them apples?

“I live on a fruit orchard,” wrote Soon Choi. “I learned that the apples you buy all spring and summer were grown last fall and put in a cold storage room with the oxygen sucked out until the spring... unless you buy them from South America.”

Quora respondents are required to use their true names under the site’s Real Names policy. To help ensure legitimacy and quality, Quora asks some individuals, such as doctors and lawyers, to confirm their expertise.